1 /* Implement fopen_unlocked and related functions.
2 Copyright (C) 2005, 2011 Free Software Foundation, Inc.
3 Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.
4
5 This file is part of the libiberty library.
6 Libiberty is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Library General Public
8 License as published by the Free Software Foundation; either
9 version 2 of the License, or (at your option) any later version.
10
11 Libiberty is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Library General Public License for more details.
15
16 You should have received a copy of the GNU Library General Public
17 License along with libiberty; see the file COPYING.LIB. If
18 not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
19 Boston, MA 02110-1301, USA. */
20
21 /*
22
23 @deftypefn Extension void unlock_stream (FILE * @var{stream})
24
25 If the OS supports it, ensure that the supplied stream is setup to
26 avoid any multi-threaded locking. Otherwise leave the @code{FILE}
27 pointer unchanged. If the @var{stream} is @code{NULL} do nothing.
28
29 @end deftypefn
30
31 @deftypefn Extension void unlock_std_streams (void)
32
33 If the OS supports it, ensure that the standard I/O streams,
34 @code{stdin}, @code{stdout} and @code{stderr} are setup to avoid any
35 multi-threaded locking. Otherwise do nothing.
36
37 @end deftypefn
38
39 @deftypefn Extension {FILE *} fopen_unlocked (const char *@var{path}, @
40 const char * @var{mode})
41
42 Opens and returns a @code{FILE} pointer via @code{fopen}. If the
43 operating system supports it, ensure that the stream is setup to avoid
44 any multi-threaded locking. Otherwise return the @code{FILE} pointer
45 unchanged.
46
47 @end deftypefn
48
49 @deftypefn Extension {FILE *} fdopen_unlocked (int @var{fildes}, @
50 const char * @var{mode})
51
52 Opens and returns a @code{FILE} pointer via @code{fdopen}. If the
53 operating system supports it, ensure that the stream is setup to avoid
54 any multi-threaded locking. Otherwise return the @code{FILE} pointer
55 unchanged.
56
57 @end deftypefn
58
59 @deftypefn Extension {FILE *} freopen_unlocked (const char * @var{path}, @
60 const char * @var{mode}, FILE * @var{stream})
61
62 Opens and returns a @code{FILE} pointer via @code{freopen}. If the
63 operating system supports it, ensure that the stream is setup to avoid
64 any multi-threaded locking. Otherwise return the @code{FILE} pointer
65 unchanged.
66
67 @end deftypefn
68
69 */
70
71 #ifdef HAVE_CONFIG_H
72 #include "config.h"
73 #endif
74 #include <stdio.h>
75 #ifdef HAVE_STDIO_EXT_H
76 #include <stdio_ext.h>
77 #endif
78
79 #include "libiberty.h"
80
81 /* This is an inline helper function to consolidate attempts to unlock
82 a stream. */
83
84 static inline void
unlock_1(FILE * const fp ATTRIBUTE_UNUSED)85 unlock_1 (FILE *const fp ATTRIBUTE_UNUSED)
86 {
87 #if defined(HAVE___FSETLOCKING) && defined(FSETLOCKING_BYCALLER)
88 if (fp)
89 __fsetlocking (fp, FSETLOCKING_BYCALLER);
90 #endif
91 }
92
93 void
unlock_stream(FILE * fp)94 unlock_stream (FILE *fp)
95 {
96 unlock_1 (fp);
97 }
98
99 void
unlock_std_streams(void)100 unlock_std_streams (void)
101 {
102 unlock_1 (stdin);
103 unlock_1 (stdout);
104 unlock_1 (stderr);
105 }
106
107 FILE *
fopen_unlocked(const char * path,const char * mode)108 fopen_unlocked (const char *path, const char *mode)
109 {
110 FILE *const fp = fopen (path, mode);
111 unlock_1 (fp);
112 return fp;
113 }
114
115 FILE *
fdopen_unlocked(int fildes,const char * mode)116 fdopen_unlocked (int fildes, const char *mode)
117 {
118 FILE *const fp = fdopen (fildes, mode);
119 unlock_1 (fp);
120 return fp;
121 }
122
123 FILE *
freopen_unlocked(const char * path,const char * mode,FILE * stream)124 freopen_unlocked (const char *path, const char *mode, FILE *stream)
125 {
126 FILE *const fp = freopen (path, mode, stream);
127 unlock_1 (fp);
128 return fp;
129 }
130